In manufacturing assembly, contours and locations of components, tooling, and machining should be accurately measured and positioned to match assembly specifications. Laser trackers are a particularly accurate method of measuring a position, and are often used in portable measurement systems.
A laser tracker generally operates by measuring a time for a laser beam to make a round trip from a reflector device. The reflector device is generally a retro-reflector, which is a device that reflects a light ray back in a direction of a source of the light ray. In other words, the light ray is reflected back along a vector that is parallel to but opposite in direction from the source of the light ray. A laser tracker can measure a distance and a direction to the retro-reflector. In this manner, the laser tracker can measure a location of the retro-reflector relative to the laser tracker.
For manufacturing assembly, a retro-reflector is positioned on an assembly component and a measured position/location is adjusted to match assembly specifications. When the measured position matches the assembly specifications to a sufficient accuracy, a mark such as a small dent is used to mark the location. The location can then be used in assembly by drilling, machining, fastening to another part, and the like.
Retro-reflectors are generally mounted in a spherical housing often referred to as a spherically mounted retro-reflector (SMR). The SMR may be mounted on a stable holder often referred to as an SMR nest. Existing processes for precision positioning of an existing SMR nest often require multiple technicians to perform the process. While one technician holds the existing SMR nest in a desired location, another technician inserts a duplicating punch into the existing SMR nest, and strikes the duplicating punch with a hammer marking the location with a small indentation. In addition to potentially damaging or leaving a permanent mark on the surface being worked, the existing process can also result in miss-located holes or parts. The existing process may also be very inefficient because of a need for additional labor and the associated labor cost.
Thus, there is a need for an SMR nest that can be efficiently used by a single operator, and does not cause damage or leave a permanent mark on the surface being worked.